"G, Manjunath Kondaiah" <manjugk@xxxxxx> writes:
> Enable runtime pm and use pm_runtime_get and pm_runtime_put
> for OMAP DMA driver.
>
> Signed-off-by: G, Manjunath Kondaiah <manjugk@xxxxxx>
> Cc: Benoit Cousson <b-cousson@xxxxxx>
> Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
> Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> ---
> arch/arm/plat-omap/dma.c | 13 +++++++++++++
> 1 files changed, 13 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> index 41b14b0..feac7ee 100644
> --- a/arch/arm/plat-omap/dma.c
> +++ b/arch/arm/plat-omap/dma.c
> @@ -35,6 +35,7 @@
> #include <linux/io.h>
> #include <linux/slab.h>
> #include <linux/delay.h>
> +#include <linux/pm_runtime.h>
>
> #include <asm/system.h>
> #include <mach/hardware.h>
> @@ -367,6 +368,8 @@ int omap_request_dma(int dev_id, const char *dev_name,
> chan = dma_chan + free_ch;
> chan->dev_id = dev_id;
>
> + pm_runtime_get(&pd->dev);
The _get() call is asynchronous. So if the device was actually
idled/disabled, immediately after this call it may still be
idle/disabled. When using the asynchronous versions of the API, the
device should not be touched until the driver's ->runtime_resume()
callback is called.
> if (d->dev_caps & IS_WORD_16)
> p->clear_lch_regs(free_ch);
> else
> @@ -452,6 +455,7 @@ void omap_free_dma(int lch)
> omap_clear_dma(lch);
> p->clear_dma_sglist_mode(lch);
> }
> + pm_runtime_put(&pd->dev);
> spin_lock_irqsave(&dma_chan_lock, flags);
> dma_chan[lch].dev_id = -1;
> dma_chan[lch].next_lch = -1;
> @@ -819,6 +823,11 @@ static int __devinit omap_system_dma_probe(struct platform_device *pdev)
> dma_chan_count = d->chan_count;
> dma_chan = d->chan;
>
> + /* Enable run time PM */
comment is redundant
> + pm_runtime_enable(&pd->dev);
> +
> + /* Accessing hw registers, get clock */
comment is wrong, driver doesn't know anything about clocks.
Just drop comment as it doesn't tell you anything that the following
'get' doesn't.
> + pm_runtime_get(&pd->dev);
see above Re: async calls.
> for (ch = 0; ch < dma_chan_count; ch++) {
> unsigned long flags;
> omap_clear_dma(ch);
> @@ -846,6 +855,10 @@ static int __devinit omap_system_dma_probe(struct platform_device *pdev)
> dma_chan[0].dev_id = 0;
> dma_chan[1].dev_id = 1;
> }
> +
> + if (!omap_dma_reserve_channels)
> + pm_runtime_put(&pd->dev);
> +
So if the reserve channels feature is used, PM is essentially disabled
for sDMA. You should add a warning here to that effect as well.
> return 0;
>
> exit_release_region:
Kevin
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